Nodule found in right side of pelvic wall. Thinking its endo is a nodule a tumor/another word for tumor?

Nodule=Lump. A nodule is a generic name for a "lump" which can occur due to a tumor (growth); tumors can be benign or malignant (cancer). However, nodules may occur secondary to inflammation or many other processes. If you have a history of endometriosis, this may very well cause a nodule in the pelvis.